In a lengthy post on its Facebook page, the company said the guard noticed a vehicle was following him when he arrived at the dairy farm. After completing his patrol the officer noticed the vehicle was parked near the entry – seemingly waiting for him.

While the officer locked up the exit gate, he heard a sound behind him before he was hit in the head.

David McCann, security chief at Ontel, told FOX40 the guard somehow managed to hit the panic button on his radio – alerting backup, which arrived at the dairy farm minutes later.

“The first Ontel unit arrived on scene and found the guard unconscious behind his car,” he added.

The guard was taken to a local hospital for treatment and was later released, Ontel said.

According to the company, the guard’s dash camera was completely ripped out of the vehicle and his body camera was also stolen.

McCann told FOX40 the guard suffered a concussion along with cuts and bruises, but is expected to make a full recovery.

“Waking up to hear this, it’s very difficult to deal with,” he said. “I don’t want anything to happen to our personnel just like I don’t want anything to happen to anyone else.”

The company said they don’t believe the guard was targeted and have handed the investigation over to the Stanislaus County Sheriff’s Department. It wasn’t immediately clear if anything had been taken from the dairy farm.